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The left shows that the super-resolution image is gradually obtained by the wavefront correction, which is guided by maximizing the gradient of the recorded image. The right shows the corresponding gradient of the recorded image

Probing Phonon Dynamics in Individual Single-Walled Carbon Nanotubes

Interactions between elementary excitations, such as carriers, phonons, and plasmons, are critical for understanding the optical and electronic properties of materials. The significance of these interactions is more prominent in low-dimensional materials and can dominate their physical properties due to the enhanced interactions between these excitations. One-dimensional single-walled carbon nanotubes provide an ideal system for studying such interactions due to their perfect physical structures and rich electronic properties. Here we investigated G-mode phonon dynamics in individual suspended chirality-resolved single-walled carbon nanotubes by time-resolved anti-Stokes Raman spectroscopy. The improved technique allowed us to probe the intrinsic phonon information on a single-tube level and exclude the influences of tube–tube and tube–substrate interactions. We found that the G-mode phonon lifetime ranges from 0.75–2.25 ps and critically depends on whether the tube is metallic or semiconducting. In comparison with the phonon lifetimes in graphene and graphite, we revealed structure-dependent carrier–phonon and phonon–phonon interactions in nanotubes. Our results provide new information for optimizing the design of nanotube electronic/optoelectronic devices by better understanding and utilizing their phonon decay channels

Extrinsic Nonlinear Kerr Rotation in Topological Materials under a Magnetic Field

Topological properties in quantum materials are often governed by symmetry and tuned by crystal structure and external fields, and hence, symmetry-sensitive nonlinear optical measurements in a magnetic field are a valuable probe. Here, we report nonlinear magneto-optical second harmonic generation (SHG) studies of nonmagnetic topological materials including bilayer WTe2, monolayer WSe2, and bulk TaAs. The polarization-resolved patterns of optical SHG under a magnetic field show nonlinear Kerr rotation in these time-reversal symmetric materials. For materials with 3-fold rotational symmetric lattice structure, the SHG polarization pattern rotates just slightly in a magnetic field, whereas in those with mirror or 2-fold rotational symmetry, the SHG polarization pattern rotates greatly and distorts. These different magneto-SHG characters can be understood by considering the superposition of the magnetic field-induced time-noninvariant nonlinear optical tensor and the crystal-structure-based time-invariant counterpart. The situation is further clarified by scrutinizing the Faraday rotation, whose subtle interplay with crystal symmetry accounts for the diverse behavior of the extrinsic nonlinear Kerr rotation in different materials. Our work illustrates the application of magneto-SHG techniques to directly probe nontrivial topological properties, and underlines the importance of minimizing extrinsic nonlinear Kerr rotation in polarization-resolved magneto-optical studies

Additional file 10: of Estrogen-induced miR-196a elevation promotes tumor growth and metastasis via targeting SPRED1 in breast cancer

Figure S10. The densities of CD31 levels were analyzed in tumor tissues with changes of miR-196a. MCF7/miR-196a, MCF7/miR-NC, MCF7/anti-miR-196a, or MCF7/anti-miR-NC cells were dispersed in 100 μl of serum-free DMEM medium and subcutaneously injected into the sides of posterior flank of nude mice (n = 4). The tumors were excised and sent to H&E (bar = 1000 μm) and immunohistochemistry to analyze the expression levels of CD31after 17 days. The densities of CD31 levels were quantified by ImageJ software, and presented as the means ± SD from 8 tumor tissues. (TIFF 1043 kb

Additional file 3: of Estrogen-induced miR-196a elevation promotes tumor growth and metastasis via targeting SPRED1 in breast cancer

Figure S3. MiR-196b has no response to E2 treatment in ER+ BC cells. (A) ER+ BC cells MCF7 and ER- BC cells MDA-MB-231 were cultured with estrogen-free medium for 72 h before E2 treatment, then treated with 10 nM E2 or equal amount of solvent Eth as solvent control for 0, 3, 6, 12 or 24 h. The expression levels of miR-196b were analyzed by qRT-PCR and U6 levels were used as internal control, and normalized to the values of the Eth control. Data were presented as the means ± SD from three independent experiments with triple replicates per experiment. * and ** indicate significant difference compared to the 0 h group at P < 0.05 and P < 0.01, respectively. (JPEG 37 kb

Additional file 9: of Estrogen-induced miR-196a elevation promotes tumor growth and metastasis via targeting SPRED1 in breast cancer

Figure S9. The correlation between SPRED1 and ESR1 expression levels. (A) Pearson’s correlation analysis was used to determine the correlation between the expression levels of ERα and SPRED1 expression levels. (JPEG 62 kb

Additional file 1: of Estrogen-induced miR-196a elevation promotes tumor growth and metastasis via targeting SPRED1 in breast cancer

Figure S1. MiR-196a is up-regulated in ER+ BC tissues. (A, B) Two different GEO2R datasets GSE58215 and GSE40267 were used to analysis the expression levels of miR-196a in ER-negative or ER-positive tissues. * and ** indicate significant difference compared to the 0 h group at P < 0.05 and P < 0.01, respectively. (JPEG 88 kb

Additional file 7: of Estrogen-induced miR-196a elevation promotes tumor growth and metastasis via targeting SPRED1 in breast cancer

Figure S7. SPRED1 reverses miR-196a-induced malignant phenotype of BC cells. MiR-196a- or miR-NC-overexpressing MCF7 cells were transfected with vector or SPRED1 cDNA without 3’-UTR. (A-B) The expression levels of SPRED1, c-Raf, pERK1/2 and GAPDH were determined by Western blot analysis after 48 h of transfection. (C-D) Cell viability was detected using CCK-8 assay. (E-F) Cells were treated and wound healing assay was performed as above. (G-H) Transwell invasion assay was performed as above using control cells and cells overexpressing miR-196a with or without SPRED1 overexpression. Data were presented as the means ± SD from three independent experiments with triple replicates per experiment. * and ** indicate significant difference between the miR-NC + Vector group and the miR-196a + Vector group with P < 0.05 and P < 0.01, respectively. # and ## indicate significant difference between the miR-196a + Vector group and the miR-196a + SPRED1 group with P < 0.05 and P < 0.01, respectively. (JPEG 552 kb

Additional file 8: of Estrogen-induced miR-196a elevation promotes tumor growth and metastasis via targeting SPRED1 in breast cancer

Figure S8. The typical targets of miR-196a shows no change with E2 treatment in ER+ BC cells. (A) The MCF7 cells were cultured with estrogen-free medium for 72 h before E2 treatment, then treated with 10 nM E2. After 24 h, the expression levels of some reported targets of miR-196a were analyzed by qRT-PCR. (B) ER+ BC cells MCF7 were cultured with estrogen-free medium for 72 h, then treated with 10 nM E2 or equal amount of solvent Eth for 24 h. The expression levels of miRNAs which were reported to be involved in regulation of SPRED1 were analyzed by qRT-PCR and normalized to the values of the Eth control. (JPEG 105 kb